Revaprazan, whose chemical name is 5,6-dimethyl-2-(4-fluorophenylamino)-4-(1-methyl-1,2,3,4-tetrahydroisoquinolin-2-yl)pyrimidine, is represented by the following Formula 1. Revaprazan may be used in a form of an acid addition salt, including e.g., HCl salt (see International Publication No. WO 1996/05177).

Revaprazan or its salt is reversibly bound to a H+/K+ exchange site of a proton pump (H+/K+ ATPase) existing in a gastric parietal cell so that secretion of H+ into the gastric lumen is competitively inhibited. Revaprazan or its salt is also bound to a specific site of H+/K+ ATPase, thereby inhibiting transport of H+ and suppressing an acid secretion to the gastric lumen, which results in increasing the intragastric pH. Unlike irreversible proton pump inhibitors, e.g., omeprazole, revaprazan or its salt is not dependent upon acid activation of a drug in a stomach or secretion status of a proton pump. Therefore, based on the mechanism different from irreversible proton pump inhibitors, such as omeprazole, revaprazan or its salt is classified into an acid pump antagonist (APA).
Meanwhile, revaprazan has very low water-solubility, i.e. less than 0.2 mg/mL, and due to such a low solubility, its dissolution in a gastrointestinal tract is low. Therefore, when revaprazan is orally administered, its absorption rate is relatively low. Revaprazan also has strong adhesion and agglutination properties, and thus, when revaprazan is formulated into a capsule or a tablet, it may be stuck to a punch or a die, thereby showing low formulation processability.